Phospholipids pack together to form a phospolipid bilayer, with the hydrophilic heads facing the water and the hydrophobic tails facing away from the water.

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Proteins Within Plasma Membranes

2 FORMS

1. Intrinsic = in the whole of the bilayer

2. Extrinsic = on one side of the bilayer only

GLYCOPROTEIN = carbohydrate chain + protein

Involved in cell recognition

other molcules join to glycroproteins because of this

involved in cell-to-cell signalling

involved in cell adhesion

GLYCOLIPID = carbohydrate chain + glycolipid

(glyco = carbohydrate chain)

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Membranes In and Around Cells

AT THE SURFACE

membranes help to separate a cell from its surroundings - like plasma or tissue fluid

WITHIN THE CELL

Provide 'compartments' allowing complex processes within the cell to be separated

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Eukaryotic Cells

Eukaryotic = true nucleus

ORGANELLES OF THE ULTRASTRUCTURE OF A TYPICAL EUKARYOTIC CELL:

1. Cell surface membrane

2. Cytoplasm

3. Nuclear membrane

4. Nucleolus

5. Nuclear pore

6. Mitochondrion

7. Secretory vesicles

8. Vesicle

9. Rough endoplasmic reticulum

10. Smooth endoplasmic reticulum

11. Golgi apparatus (body)

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Collaboration of Organelles Within Eukaryotic Cell

To perform functions, organelles often have to work together.

Antibody production is an example of this...

INVOLVING:

Nucleus holds gene that codes for protein on chromosomes --> messenger molecule takes code to ribosome on rough endoplasmic reticulum --> proteins made --> transported to golgi apparatus in small sacks called vesicles --> proteins are modified and repackaged --> make their way to the cell surface membrane

THE ENERGY ENABLING ALL OF THIS TO OCCUR IS PRODUCED BY THE MITOCHONDRIA (ATP)